Electrical system of distribution.



A. s. HUBBARD.

ELECTRICAL SYSTEM 0I' DISTRIBUTION.

'APPLIGATION FILED JAN. 29, 1908.

Patented Sept. 29, 1908.

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UNITED STATES IJATENT OFFICE.

ALBERT S. HUBBARD, OFBELLEVILLE, NEW JERSEY, ASSIGNOR TO GOULD STORAGE BAT- TERY COMPANY, A CORPORATION OF NEW YORK.

ELECTRICAL SYSTEM OF DISTRIBUTION.

Specincation of Letters Patent.

Patented sept. 29, 190s.

Application led January 29, 1908. Serial No. 413,211.

To all whom it muy consom:

Be it known that I, ALBERT S. HUBBARD, a citizen of the United States, and a resident of Belleville, county of Essex, State of New Jersey, have invented certain new and useful -Improvements in Electrical Systems of Dis.

dynamo arranged to give out different char-- acters of current, as for example alternating and direct currents, and I regulate a battery which is connected to and supplies only one of the circuits so as to maintain the total currents or loads of the two circuits substantially constant, by varying the battery ac tion to vary the current outputof one circuit according as the total load on both circuits varies.

The specific combination which I have invented comprises a dynamo having a commutator whose brushes form the terminals of a D. C. circuit and slip rings which supply an A. C. circuit. Across the D. C. circuit isfa branch containing a battery and booster, the booster being regulated in any suitable way responsive to current or load fiuctuations on the two generator circuits.

In such a system a single booster only is necessary Whatever the characteristics of the two sides of the system, and it is unnecessary to provide load carrying rectifyingdevices between the A. C. and D. C. sides of the system or to place the battery in direct `operative relation with the A. C. circuit.

These and more specific features of my invention will be more full ex lainedgin the detailed description whic fol ows. z

'The drawing accompan ing this specification is a diagram which i ustrates a's'y'stem steam engine 'or any othersui-table-form'.

Directly connected to thisand,v operated thereby is an alternatingfdirectfcurrent generator B furnishing an 'alternating current at 'present instance this is accom one end through the slip rings b and brushes b, to the alternating current mains '1. At

the other end of the generator B is a commutator b2 from which a direct current is taken by means ofthe brushes b3 and furnished to the direct current mains 2. ConnectedA across the direct current mains 2 is a battery C and in series therewith the armature D of a 'booster which may be driven in any well known manner, as by a motor or otherwise. This booster is rovided with a field D connected across tlie direct current mains and having in series therewith the armature of a counter-electronictive-force generator, E.

`This counter-electromotive-force generator is provided with .two field windings, one of which, E', .is connected in series in on of the direct current mains, 2, and is thereare responsive to current changes lin thedirat current circuit'. The other field winding E2 is connected ythrough a rectifying device to the alternating current" mains as hereinafter more fully described. These two coils E and E2 act cumulativcly..

. At 3 I have shown .transformers Whose primaries are connected inseries in the alternating current mains and whose secondaries -are Vconnected to distributedwindings on the which is diagrammatically indicated` at Some outside means must -be rovided to drive the rectifier synchronous In the lished by the synchronous motor G driven om the alternating current circuit. This motor drives the rectifier so that it rotates synchronously with' the voltage' of the alternatin current circuit. The regulating field coil is connected to brushesf bearin on the commu# tator F of the rectifier. -hese brushes are preferably placed inl the vusual position,

namely, at the points of normal maximum voltage; This rectilier placed in theregu lating circuit and employed to provide a cur- -rent to the re latin coll E is more full described toget er wit its incumbent -tages in my Patent'No. 869,244,`dated Oct.

29, 1907 -If then the power factor is unity -a' currentwill be produced inthe' coil Epro portional to and -varying with the current in .thealternating current mains.. 'Ifthepower .vall- -factorof the-alternating side of the system -changes the'brushes will no lodger'be at the points of maximumv ifference of pntential but these pointsv will be shifted to one side of said brushes. The brushes, f, will then have a smaller difference of potential between them and thevcurrent furnished the coil E2 will be 5 decreased in thesame Aproportion as the energy current (as distinguished from wattless current) of the alternating current mains is decreased. The eXtra currentfurnished to the rectifier and .proportional to the wattless current is taken off by the brushes f and allowed to dissipate in the' by-pass circuit f2 t and adjustable resistance f 3, thesebrushesf now having some difference of potential be'- tween them due to the change in power factor and shifting of the points pf maximum difference'of potential, It will therefore be seen that the current in coil E2 varies in accordance with changes ofL the current in transformers 3 only when there is no change of power factor. If, however, there is 4a coincident l change of current and change of power factor the current in the coil E2will be a resultant of these changes, an increase of current in the alternating current circuit tending to increase the current lin coil E2 while a decrease of power factorA tends to decrease it. In `this way the regulation is not aectedfby the wattless current component 'of the apparent energy. n i l When both the alternating and direct current circuits are operating under normal load the coils E and E2 furnish a ield for the generator E of such a strength that it will produce Y a voltage just equal and opposed to the voltage of the direct current mains. .No current will therefo'reflow through the coil -D and the booster will oatf across the line. If the load on either side of the system increases or decreases the field E or E2 is cor- 40 respondingly increased or decreased and the booster is operated in theusual well-known manner, to either add voltage to the battery so that it will take the additional load, or to oppose the battery voltage so that the bat'- tery will be charged from the mains. It will also be noticed that if the load on one side of the system increases by a certain amount and the load on the other side of the system decreases 4by the same amount the total field strength of the generator E will remain practically unchanged; and in any case the total field strength of the generator E varies as the sum of the loads on the two sides of the system. Thus when the load on the generator B or prime mover A is increased the booster is operated to add voltage to the battery so that it lmay takev the additional load and when -the load on the generator or prime mover decreases the booster is o )erated to oppose the battery sothat it will be charged from the direct current mains and tend to bring the load on the generator or prime mover, A, up to. normal. This regulating action takes place irres ective of whether the G5 change of load takes p ace on one side of the system or the other, or on both sides of the system simultaneously.

Each load circuit takes its current directly from the generator or generating means and no rectifier or converter is necessary between v the two sides of the system, which carries load currents. Therefore the losses occurring in such a rectifier are wholly eliminated.

The generating means for both sides of the system may consist simply of a single generator'having both direct and alternating current terminals. By the use of this structure the iron losses due to two or more'se arate generators are materially decreased, alt ough my invention in its broadest aspects is not limited to the use of a single generator.

It is obvious that thel principles of my invention as herein described may be applied to many different specific systems elther where voltage or where current regulation is the dominatingregulation. I do not, therefore, limit myself to the specific features shown and described but What I claim as new and desire to protect t by Letters Patent is: Y

l. The combination of a generator, two independent circuits sup lied thereby, a battery connected to one onlly of said circuits, a booster in series With'the battery and adapted to control-the charge and discharge there- 95 of, and means for regulating the booster responsively to current changes in both of said circuits.

2. The combination of a, generator, two independent circuits supplied thereby, aA battery connected to one on y ofsaid circuits, a booster in series Withthe battery and adapted to control the charge and discharge thereof, a coil in each of sald circuits and regulating apparatus for said booster affected by the current in each of said coils.l

3. The combination of a generator, two independent circuits supplied thereby, abattery connected to one only of said circuits, a booster in series withthe .battery and adapted to control the charge and discharge thereof, and means for governing'said booster for maintaining an approximately constant load on the generator. V

4. The combination of a generator, two independent circuits supplied thereby, a battery connected to one on y of said circuits, a booster in series with the battery and adapted to control the charge and discharge thereof, a generator in series with the fieId o f th'e 120 booster, and means for varying n the field strength of said generator in accordancewith variations of the total load of the two independent circuits.

5. The combination of an alternating-direct current generator, alternating and direct current circuits therefor, a battery and a booster connected to the direct current cirt cuit, a generator in series with the booster field part of the field of said generator being v responsive to changes in the direct current and part responsive to changes in the load on the alternating current circuit.

6. The combination of a double current generator, two independent circuits therefor,

lprime mover, a direct current generating means and an alternating .current generating means directly operatedthereby, va direct and an alternating current circuit respectively for said generating means, a booster and battery in the direct current circuit and means for governing said booster subject to load iluctuations 'in both of said circuits.

8.l In a system of electrical distribution, a prime mover, a direct and an alternating current generating means mechanically operated thereby, a battery and booster connected to the direct current generating means, a generator in series with the field of Y the booster, part'of the field of said generator being responsive to changes in the current-of the direct current generating means and part being res onsive ,to changes in the power develop'ed y the alternating current generating means, regardless of the size of the power factor.

9. The combination of a generator,.'two independent circuits supplied thereby, a storage apparatus connectedto one of said circuits, a booster in series with the storage apparatus and means' for regulatingi the booster responsive to changes in the electrical condition of both of said circuits.

l0. The combinationI of a generator, two independent circuits supplied thereby, one of said circuits being an A. C. circuit, astorage apparatus and a booster connected to the other circuit, a generator for governing said booster, said generator being responsive to load changes 1n both circuits regardless of power factor changes.

In testimony whereof, I have signed my nameto this specification, in the presence of two subscribing witnesses..

ALBERT S. H UBBARD.

Witnesses:

GORHAM CROSBY,

EDWIN SEGER. 

